Sen. Chuck Grassley, ranking Republican member on the Senate Judiciary Committee, left, pauses after a heated exchange Monday during the committee's hearing on immigration reform. Committee Chairman Patrick Leahy, D-Vt. is at right.

Written by

Aamer Madhani and Alan Gomez
USA TODAY

The White House on Monday pushed back against suggestions from some Republican lawmakers that last week's bombings at the Boston Marathon should slow down the conversation on an overhaul of the nation's immigration laws.

Sen. Rand Paul, R-Ky., suggested on Monday that last week's bombings - which authorities suspect was carried out by two young Chechen immigrants - casts a shadow on the immigration debate.

"Before Congress moves forward, some important national security questions must be addressed," Paul wrote in letter to Senate Majority Leader Harry Reid. "The facts emerging in the ...